In the garment care industry, both starch and sizing agents play important roles in enhancing the appearance and finish of fabrics. While they serve similar functions, these products differ in composition, application, and the effects they impart on various textiles. Understanding these differences can help in selecting the appropriate agent for a specific fabric or garment.

Starch: Composition and Application

Starch is a plant-based stiffening agent commonly derived from sources such as corn, wheat, or rice. Its primary purpose is to impart stiffness to fabrics, which is achieved when the starch is cured using heat from a shirt unit, hand iron, or pressing machine. The use of starch results in a crisper feel, but excessive application can make the fabric overly stiff and more susceptible to creasing.

Starch is most effective on plant-based fibers, including cotton, linen, and ramie. Fabrics containing synthetic fibers or blends of natural and synthetic materials do not accept starch as readily as those made from natural fibers. To address this, manufacturers offer synthetic liquid starches designed to provide stiffness for synthetic or blended fabrics.

Sizing Agents: Properties and Benefits

Sizing agents are typically made from resins that can be derived from either synthetic or natural sources. Unlike starch, sizing agents add body, crispness, and “hand” (the way a fabric feels to the touch) to a fabric without causing significant stiffening. Like starch, these agents are also cured with heat.

Laundering and Wet Cleaning Applications

The most effective way to use starch or sizing agents during laundering and wet cleaning is to manually add or inject the product into the washing machine using the appropriate program. Alternatively, spray starches and sizing agents can be applied during the finishing stages (pressing and ironing). These sprays are available in various forms, including pump sprays, aerosol sprays, or mixtures that can be applied with a pressurized spray tank. However, the spray method is generally less effective, as the product may not be fully absorbed by the fabric. Additionally, buildup of these agents on finishing equipment may lead to premature failure of the padding.

Drycleaning Applications

In drycleaning, sizing agents compatible with drycleaning systems are widely used. They can be added to the solvent tank using the “charge” method, the injection method, or by manually introducing the product into the drycleaning machine on a “batch” basis. Since sizing agents can create an undesirable feel on woolens and knitted fabrics, it may be necessary to exclude such garments from cleaning in a charged tank. An alternative is to use a batch cycle, which is especially effective for items like draperies or hard-finished fabrics that benefit from sizing agents without causing buildup in the solvent tank.

Conclusion

In summary, both starches and sizing agents are valuable tools for enhancing the appearance and qualities of fabrics and assisting in garment finishing. The choice between them depends on the desired effect: starch is best for providing stiffness and crispness, whereas sizing agents are ideal for adding body, crispness, and a pleasant “hand” without making the fabric feel harsh or overly stiff.